1. Field of the Invention
The present invention provides an airflow guiding device, and more particularly, to a guiding device for use in a projector, which can guide an airflow generated by a blower to a bulb for cooling the bulb.
2. Descriptions of the Related Art
In reference to FIG. 1A, in conventional projectors 1, high temperatures are generated during the operation of a bulb 20 which causes damage to the bulb 20 and/or other internal components. Therefore, the conventional projector 1 must be provided with a blower 10 so that airflow generated by the blower 10 is guided by a pipe 11 and a guiding device 30 towards the bulb 20 to lower the temperature of the bulb 20.
In reference to FIG. 1B, in detail, the bulb 20 has a front end 201 and a rear end 202. The gas for light emission is more concentrated on the upper portion 202a of the bulb 20, so when a high temperature is generated during the operation of the bulb 20, the upper portion 202a of the bulb 20 has a first temperature higher than a second temperature of a lower portion 202b of the bulb 20. When airflow generated by the blower 10 flows through the pipe 11 to a first outlet 311 and a second outlet 312 formed on a body 31 of the guiding device 30, the first outlet 311 and the second outlet 312 generate a first airflow 111 blowing towards the front end 201 of the bulb 20 and a second airflow 112 blowing towards the rear end 202 of the bulb 20 respectively. Here, the second airflow 112 blows towards both the upper portion 202a and the lower portion 202b of the bulb 20 simultaneously, so although this can lower the temperature of the bulb 20 itself, the difference between the first temperature of the upper portion 202a and the second temperature of the lower portion 202b cannot be reduced. Consequently, a large difference in the temperature can decrease the service life of the bulb 20.
Therefore, as shown in FIG. 1C, in the prior art, a fixed baffle 32 is disposed on the lower portion of the second outlet 312 of the guiding device 30. The second airflow 112 only blows toward the upper portion 202a of the bulb 20 but not towards the lower portion 202b of the bulb 20. Thereby, the difference in temperature between the upper portion 202a and the lower portion 202b is reduced and thus the service life of the bulb 20 is prolonged.
As shown in FIG. 1D, when the projector 1 is used upside down (e.g., hung upside down from a ceiling), the bulb 20 has a temperature distribution similar to what is described above: the upper portion 202a of the bulb 20 has a first temperature higher than a second temperature of the lower portion 202b of the bulb 20. However, it shall be noted that due to the upside-down orientation, the fixed baffle 32 of the guiding device 30 is now located at the upper portion of the second outlet 312; therefore, the fixed baffle 32 will guide the second airflow 112 towards the lower portion 202b of the bulb 20 to further lower the second temperature which is already lower than the first temperature of the upper portion 202a. Consequently, the difference in temperature between the upper portion 202a and the lower portion 202b is actually larger than the difference in temperature before the fixed baffle 32 is provided, and this further shortens the service life of the bulb 20 significantly.
In view of this, there is an urgent need in the art to provide a solution to effectively control the airflow direction such that the difference between the first temperature of the upper portion of the bulb and the second temperature of the lower portion of the bulb can be minimized regardless of the usage status of the projector.